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Descrintion of the Environment <br />Climate <br />The climate at the Edna Mine is typical of semi-arid steppe regions with more than half of <br />the annual precipitation (16 inches) falling as snow. The temperatures aze cool, from 61 F <br />average mean temperature in August, to a cold 18 F average mean in February. Regional <br />winds aze from the west. Local topography affects both precipitation and wind direction. <br />Ge010gy <br />The Edna Mine is geographically situated between the drainages of Oak Creek on the east <br />and Trout Creek on the west. Topographically, the permit azea is dominated by a <br />north-south trending ridge line. A steep east-facing escarpment extends to Oak Creek, <br />with a gentler west-facing dip slope from the ridge line west to Trout Creek. Elevation of <br />the azea varies from 7,000 to 7,600 feet. <br />Except for surficial deposits, only the coal beazing Cretaceous Mesaverde Group outcrops <br />in the permit azea. The Williams Fork Formation and the Iles Formation together <br />comprise the Mesaverde Group. The Williams Fork Formation is sepazated from the <br />lower Iles Formation by the massive Trout Creek Sandstone Member, the top of which <br />forms the upper limit of the Iles Formation. The coals seams that were mined at the Edna <br />Mine aze all situated within the Williams Fork Formation, approximately 150-225 feet <br />above the Trout Creek Sandstone. The "Middle Coal Group" of the lower coal bearing <br />member includes, in ascending order, the Wolf Creek, Wadge, and Lennox coal seams. <br />The Lennox and Wadge seams were mined in the West Ridge Area. The Wadge seam <br />was mined in the Moffat Area. <br />The major portion of the Edna Mine is located on the eastern limb of the Twentymile <br />Park Syncline, the axis of which trends northwest from the southernmost boundary of the <br />permit azea through West Ridge. Two minor faults occur in the Moffat Area of the mine <br />site. <br />Landscape chazacter in and near the Edna Mine results mostly from moderate folding of <br />strata followed by differential erosion of interbedded resistant and non-resistant layers of <br />various thicknesses. The southern portion of the permit azea, West Ridge, consists of <br />lazge azeas of previously strip-mined land chazacterized by spoil ridges from a dragline <br />operation conducted prior to enactment of the Surface Mining Control and Reclamation <br />Act (SMCRA). <br />C-1980-001 Permit Renewal 5 Findings Page 7 of 33 Pages <br />